No Decel Valve, no problem? Except a lil popping |
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No Decel Valve, no problem? Except a lil popping |
nditiz1 |
Sep 25 2018, 09:33 PM
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#1
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Senior Member Group: Members Posts: 1,188 Joined: 26-May 15 From: Mount Airy, Maryland Member No.: 18,763 Region Association: MidAtlantic Region |
2.0 76 GC motor -
So I went through my entire FI system to find out if any vac leaks were present as well as learn the ins and outs. I did find some things interesting and enjoy what they mean except for a slight popping I get on deceleration. Now, this could be caused by two things, exhaust leak (have new gaskets to be installed) lack of decel valve. If the car still runs by removing certain items I am all for it, especially ones that are over priced due to NLA. My AAR is in good working order, but if it ever does go belly up I may just remove that too. Currently I have the cold start valve disabled (no connector, no fuel) I was trying to diagnose a rich running issue and read it only kicks in at real low temps. I can always properly test it and hook it back up if need be - one item down. I was looking for my decel valve and could never find it because I don't have one. Now, how much of a burden is this causing me. The car seems to motor down the road fairly well. It idles great (steady) after being warmed up. I get a popping inside the exhaust on deceleration. I have gone over the timing was at 27 but put it to 28 after finding out I have a Raby 9550 cam. So now I have a more simple system without two factory things, but is not having the decel valve causing more issues like the popping or even worse? What say you decel valveless FI guys (I think t_rowle runs his that way). |
jcd914 |
Sep 26 2018, 10:52 PM
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#2
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Advanced Member Group: Members Posts: 2,081 Joined: 7-February 08 From: Sacramento, CA Member No.: 8,684 Region Association: Northern California |
I am not sure about the decel valves on 914s but not all decel valves are adjustable.
The common adjustment is a bolt with a jam nut, loosen the jam nut and tighten or loosen the bolt to adjust how fast the decel valve closes after the vacuum spikes and opens it. tightening the bolt increases the spring tension on the diaphragm in the valve. Jim |
worn |
Sep 27 2018, 01:16 AM
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#3
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can't remember Group: Members Posts: 3,156 Joined: 3-June 11 From: Madison, WI Member No.: 13,152 Region Association: Upper MidWest |
I am not sure about the decel valves on 914s but not all decel valves are adjustable. The common adjustment is a bolt with a jam nut, loosen the jam nut and tighten or loosen the bolt to adjust how fast the decel valve closes after the vacuum spikes and opens it. tightening the bolt increases the spring tension on the diaphragm in the valve. Jim A helpful tool in working with the system is something like the mighty vac, which couples a vacuum pump with a gauge. Helps for setting decal valve and testing for leaks. You can for instance put different levels of vacuum on the decel valve and blow through the other port to see at what vacuum the valve opens and closes. Then you can adjust. I don’t run my decel valve and get no popping. |
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